hello , using python v.3 , i tried to merge those two functions
.sort()
.reverse()
into one line .sort()=(reverse=true)
but it doesn't execute , what would be the problem ?

I am not sure what you are trying to do and the above line does not make sense.
If you have a list of say L=[3,2,1,4] and do L.sort() L will now be [1,2,3,4]. If you do L.reverse() on the original list you will get [4,1,2,3].
If you wanted to compare if doing both are the same it would be more like.
L=[3,2,1,4]
Lsort = L[:]
Lsort.sort()
Lrev = L[:]
Lrev = Lrev.reverse()
if Lsort == Lrev:
print 'True'
else:
print 'False'